So, Joe deposits a urine sample in a small jar and takes it to Wal-Mart.

He deposits ten dollars, and the computer lights up and asks for the urine sample. He pours the sample into the slot and waits.

Ten seconds later, the computer ejects a printout:

"You have tennis elbow. Soak your arm in warm water and avoid heavy activity. It will improve in two weeks. Thank you for shopping @ Wal-Mart."

That evening, while thinking how amazing this new technology was, Joe began wondering if the computer could be fooled.

He mixed some tap water, a stool sample from his dog, urine samples from his wife and daughter, and a sperm sample for good measure.

Joe hurries back to Wal-Mart, eager to check the results. He deposits ten dollars, pours in his concoction, and awaits the results.

The computer prints the following:

1. Your tap water is too hard. Get a water softener. (Aisle 9)2. Your dog has ringworm. Bathe him with anti-fungal shampoo. (Aisle 7)3. Your daughter has a cocaine habit. Get her into rehab.4. Your wife is pregnant. Twins. They aren't yours. Get a lawyer.5. If you don't stop playing with yourself, your elbow will never get better!